Calcium, Serum or Plasma Concentration
This test measures the amount of calcium in your blood, which is important for keeping bones strong, muscles working properly, and nerves functioning correctly.
["Your calcium level helps ensure healthy bones, muscle function, and nerve signaling."]
Key facts at a glance
- LOINC
- 15035-9
- Short code
- CALC
- Synonyms
- Calcit SerPl-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube without anticoagulant for serum; EDTA or heparinized plasma tube for plasma specimens
- Units
- N/A
- Ref low
- 0
- Ref high
- 11.5
- Critical range
- — – 100 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Immunoassay (Chemiluminescent Immunoassay [CLIA] or Radioimmunoassay [RIA])
- CPT
- 82308
- SNOMED
- 39579003
- Specimen volume
- 1.0 mL serum or plasma (minimum 0.5 mL)
- Stability
- Room temperature: 8 hours; Refrigerated (2-8°C): 24 hours; Frozen (-20°C or lower): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 300
- Icterus max
- 40
- TAT
- 24–72 hours
- Order
- routine
Why Is This Test Done?
Doctors may order a calcium test to check for conditions like low or high calcium levels, which can cause symptoms such as muscle cramps, weakness, or irregular heartbeats. It may also be used to monitor bone health, kidney function, or response to treatments like calcium supplements or medications.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it involves a blood draw, but this depends on your doctor’s instructions. Bring any medications you’re taking to your appointment.
What Happens During the Test?
A healthcare provider will draw blood from a vein in your arm. The sample is then sent to a lab for analysis to measure calcium concentration in your serum or plasma.
What Are Possible Results?
Results are reported as a numerical value representing calcium concentration in milligrams per deciliter (mg/dL). Your doctor will interpret the result in relation to your health and symptoms.
Reference range
Reference ranges vary by assay method and laboratory. Typical adult reference ranges: Male: <11.5 pg/mL (<3.4 pmol/L); Female: <4.6 pg/mL (<1.4 pmol/L). Pediatric and neonatal ranges differ significantly.N/A
No fasting required. Patient should be well-hydrated. Avoid recent radioisotope administration. Pentagastrin stimulation testing may be performed for patients with borderline elevated basal calcitonin levels or for screening of family members with MEN2 syndromes.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low calcium (hypocalcemia) can lead to muscle spasms, numbness, or irregular heart rhythms, while high calcium (hypercalcemia) may cause fatigue, nausea, or kidney stones. These imbalances can stem from conditions like vitamin D deficiency, kidney disease, or certain cancers.
Short name
Calcium Level
Frequently asked questions
What causes my calcium level to be checked?
How long does it take to get my results?
Can I eat or drink before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 15, 2026. · Read our editorial policy